Is there an adjustment that sets the number of questions that can be seen on a page, or by scrolling downward? If yes, where is it?

Not anymore. There used to be though.

No, that was the old system, that let you looked by pages. It was popular with the point gamers who found it easier to cheat that way by answering 4 day old questions with no answers, scooping up all BA's, because it was the ONLY answer.

The new system is just an endless scroll. More of a chore.

No there is not you just keep Scrolling til there is nothing Left